2 routes.
some would say take 13 north to Clinton, then 7 to Harrisonville, the 49 north to K.C. Catch 29 on the south side of KC, take you to airport...
Personally I would go to springfield, take james river west to 44, exit off of 44 on exit 57 (96 hiway). take it west to carthage, just east of carthage you can cut up north by truck stop and catch 49 (old 71), roll straight north to KC, then catch 29 and into airport.
check google maps, you can see which route you prefer.